A conventional nailing depth adjusting device for a power nailer is shown in FIG. 1 and generally includes a link 10 having a distal end extending from a front of the power nailer and a second end of the link 10 has a threaded section to which a nut 12 is mounted. The threaded section is rotatably supported by a first end of a push plate 11 and a second end of the push plate 11 contacts against a trigger means. The second end of the push plate 11 is used to release to a lock status of the trigger means so that when the push plate 11 is pushed toward the trigger means, the trigger can be pushed to eject a leading nail. A spring 13 is mounted to the threaded section of the link 10 and biased between the nut 12 and the first end of the push plate 11. A cap 14 is connected to the first end of the push plate 11 and encloses the threaded section of the link 10 from dust. A longer distance the link 10 is extended from the front end of the nailer, a shorter depth that the nailer penetrates into an object contacting the link 10. The movement of the link 10 is controlled by rotating the nut 12. However, the threaded section of the link 10 could be disengaged from the first end of the push plate 11 if the user rotates the nut 12 without noting the engagement between the threaded section and the nut 12.
The present invention intends to provide a nailing depth adjusting device for a power nailer wherein the link will never drop or be disengaged from the push member.